The optical density of turpentine is higher than that of water,while its mass density is lower. The figure shows a layer of turpentine floating over water in a container. For which of the four rays incident on the turpentine as shown in the figure,is the path correct?

The $x-z$ plane separates two media $A$ and $B$ with refractive indices $\mu_1$ and $\mu_2$ respectively. $A$ ray of light travels from $A$ to $B$. Its directions in the two media are given by the unit vectors $\vec{r}_A = a\hat{i} + b\hat{j}$ and $\vec{r}_B = \alpha\hat{i} + \beta\hat{j}$ respectively,where $\hat{i}$ and $\hat{j}$ are unit vectors in the $x$ and $y$ directions. Then:

The velocity of light in a medium is $1.5 \times 10^8 \ m/s$. Its refractive index will be:

$A$ ray of light is incident upon an air/water interface (it passes from air into water) at an angle of $45^o$. Which of the following quantities change as the light enters the water?
$(I)$ wavelength
$(II)$ frequency
$(III)$ speed of propagation
$(IV)$ direction of propagation

$A$ ray of light is incident at the glass-water interface at an angle $i$. It emerges finally parallel to the surface of water. Then the value of refractive index of glass,${\mu _g}$,is:

$A$ tank is filled with water to a height of $12.5 \;cm$. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be $9.4 \;cm$. What is the refractive index of water?
If water is replaced by a liquid of refractive index $1.63$ up to the same height,by what distance would the microscope have to be moved to focus on the needle again?